AppBarLayout with recyclerView in nested fragment

Question

As images are always better than words, I present to you my current layout.

The toolbar/tabs is in an activity.xml with a viewPager, and the recycle

Answer 1

You can do this by implementing ViewPager.OnPageChangeListener and enabling/disabling AppBarLayout.LayoutParams scrolling flags.

Here is a sample code:

        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageSelected(int position) {
            if (position == 0) {
                //turn on scrolling
                AppBarLayout.LayoutParams toolbarLayoutParams = (AppBarLayout.LayoutParams) mToolbar.getLayoutParams();
                toolbarLayoutParams.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS);
                mToolbar.setLayoutParams(toolbarLayoutParams);

                CoordinatorLayout.LayoutParams appBarLayoutParams = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
                appBarLayoutParams.setBehavior(new AppBarLayout.Behavior());
                appBarLayout.setLayoutParams(appBarLayoutParams);
            } else {
                //turn off scrolling
                AppBarLayout.LayoutParams toolbarLayoutParams = (AppBarLayout.LayoutParams) mToolbar.getLayoutParams();
                toolbarLayoutParams.setScrollFlags(0);
                mToolbar.setLayoutParams(toolbarLayoutParams);

                CoordinatorLayout.LayoutParams appBarLayoutParams = (CoordinatorLayout.LayoutParams) appBarLayout.getLayoutParams();
                appBarLayoutParams.setBehavior(null);
                appBarLayout.setLayoutParams(appBarLayoutParams);
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });

But it does not seem like a good UX pattern. It will be confusing for users.